Gas liquid chromatography-mass spectrometry (GLC-MS), ion exchange chromatography, radioisotopic techniques and many separation procedures are used to develop assays and measure biogenic amines and their metabolites in cerebrospinal fluid, blood and urine. Appropriately labelled deuterium tritium or carbon 14 compounds are synthesized or prepared enzymatically for use as internal standards or for studies in patients with mental and neurologic disorders. BIBLIOGRAPHIC REFERENCES: Perlow, M.J., Festoff, B., Gordon, E.K., Ebert, M.H., Johnson, D.K. and Chase, T.N.: Daily fluctuations in the concentration of cAMP in the conscious primate brain. Brain Res. 126: 391-396, 1977. Perlow, M.J., Gordon, E.K., Ebert, M.H., Hoffman, H.J., and Chase, T.N.: The circadian variation in dopamine metabolism in the subhuman primate. J. Neurochem. 28: 1381-1383, 1977.